OpenID Connect vs SAML Authentication – Understanding the Authentication Handshake (2026 Enterprise Guide)
Modern Enterprise Identity Systems rely on Federated Authentication Protocols to enable Secure Access Across Applications and Platforms. Two of the most widely used protocols are OpenID Connect (OIDC) and SAML.
This guide explains the authentication handshake for both protocols, how they differ, and when to use each in enterprise environments.
What Is SAML?
Security Assertion Markup Language (SAML) is an XML-based authentication protocol commonly used for enterprise Single Sign-On (SSO), especially in legacy and SaaS integrations.
SAML Components:
- Identity Provider (IdP)
- Service Provider (SP)
- SAML Assertion (XML token)
SAML Authentication Handshake
Step 1 – User Access
The user attempts to access a Service Provider (e.g., SaaS application).
Step 2 – Redirect to Identity Provider
The SP redirects the user to the Identity Provider for authentication.
Step 3 – Authentication
The IdP authenticates the user (password, MFA, etc.).
Step 4 – SAML Assertion Issued
The IdP generates a signed XML SAML assertion containing identity claims.
Step 5 – Assertion Posted to SP
The browser posts the assertion back to the Service Provider.
Step 6 – Access Granted
The SP validates the signature and grants access.
Characteristics:
- XML-based
- Uses browser redirects
- Primarily for web-based enterprise apps
- Heavier message format
What Is OpenID Connect (OIDC)?
OpenID Connect is a modern authentication protocol built on OAuth 2.0 and uses JSON Web Tokens (JWT).
It is widely used for:
- Cloud-native applications
- Mobile apps
- APIs
- Microservices
OIDC Components:
- Authorization Server
- Client Application
- ID Token (JWT)
- Access Token
OpenID Connect Authentication Handshake
Step 1 – User Access
User attempts to access an application.
Step 2 – Redirect to Authorization Endpoint
Application redirects user to the OIDC provider.
Step 3 – Authentication
User authenticates with the provider.
Step 4 – Authorization Code Issued
The provider returns an authorization code to the client.
Step 5 – Token Exchange
The client exchanges the authorization code for:
- ID Token (identity)
- Access Token (API access)
- Optional Refresh Token
Step 6 – Access Granted
Application validates the JWT and grants access.
Characteristics:
- JSON-based
- Lightweight
- API-friendly
- Mobile and SPA support
- Modern cloud standard
SAML vs OpenID Connect – Key Differences
Protocol Format
SAML → XML
OIDC → JSON (JWT)
Primary Use Case
SAML → Enterprise web SSO
OIDC → Cloud-native, mobile, APIs
Token Type
SAML → XML Assertion
OIDC → JWT ID Token
Performance
SAML → Heavier payload
OIDC → Lightweight
Modern Application Support
SAML → Limited for APIs
OIDC → Native support
Security Considerations
Both support:
- Digital signatures
- Encrypted assertions
- MFA integration
- Conditional Access policies
OIDC advantages:
- Token validation simpler
- Works well with APIs and microservices
- Better for zero-trust modern architecture
SAML advantages:
- Mature enterprise adoption
- Strong SaaS compatibility
- Stable for legacy environments
When to Use Each
Use SAML when:
- Integrating legacy enterprise SaaS
- Working with older identity ecosystems
- Vendor only supports SAML
Use OpenID Connect when:
- Building modern applications
- Supporting mobile or SPA apps
- Designing API-first architecture
- Implementing zero-trust cloud environments
Enterprise Architecture Perspective
In modern Azure and Microsoft Entra ID environments:
- SAML is still widely supported for SaaS integrations.
- OIDC is preferred for modern cloud-native development.
- Most enterprise architectures will use both simultaneously.
Understanding the authentication handshake flow is critical for secure federation, token validation, and identity governance.
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